Rollover protective structures (ROPS) are useful to protect the operator of construction equipment from injury in the event of operator error such as the operator rolling the equipment. Such structures are typically fabricated of various support members attached together to form a frame surrounding the operator. The frame can be generally box-like by virtue of having four posts supporting a canopy (four-post ROPS), or can simply include two posts supporting a canopy (two-post ROPS). Regardless of the type of ROPS, the structure is desirably capable of deforming in a controlled manner under adverse loading conditions in order to protect the operator.
Whether due to geometric notches resulting from a change in cross-section across a load-path or metallurgical notches resulting from a change in material properties across a load-path, the ROPS are potentially subject to concentrated deformation at the notch location. Should the deformation at the notch location be too large, the ROPS may become unstable during deformation and ultimately collapse. Therefore, a ROPS design is desired which controls deformation at both geometric and metallurgical notches so that the ROPS deforms under adverse loading in a controlled manner.